Conventional bearing apparatuses including bearing surfaces that move relative to one another are known in the art. For example, conventional, so-called “thrust bearings” and some embodiments of radial bearings include bearing surfaces that at least partially contact and move or slide relative to one another. Such bearing surfaces may include a superhard material for resisting wear during use of the bearing apparatus. In one example, bearing surfaces in a bearing apparatus may comprise a hard material such as diamond (e.g., polycrystalline diamond).
One application for bearing apparatuses, such as thrust bearings and radial bearings, is in drilling equipment utilized in subterranean drilling. Particularly, drilling motors have been utilized for drilling boreholes into subterranean formations, especially for oil or gas exploration. In a typical downhole drilling motor, the motor is suspended at the lower end of a string of drill pipe comprising a series of pipe sections connected together at joints and supported from the surface. A rotary drill bit (e.g., a fixed cutter drill bit, roller cone drill bit, a reamer, etc.) may be supported below the drilling motor (via pipe sections, drill collars, or other structural members as known in the art) or may be directly connected to the downhole motor, if desired. Drilling fluid is commonly circulated through the pipe string and the motor to generate torque within the motor, causing the rotary drill bit to rotate. The drilling fluid may then be returned to the surface through the annular space between the drilled borehole and the drill string and may carry the cuttings of the subterranean formation to the surface.
Downhole drilling motors may include bearing apparatuses, such as thrust bearings or radial bearings. More particularly, conventional downhole drilling motors may include a non-rotating bearing ring that does not rotate and is connected to a housing of the motor and a rotating bearing ring that rotates with the output shaft of the downhole fluid motor. In one embodiment, bearing assemblies comprised of a plurality of hard bearing elements, such as diamond bearing elements, may be coupled to the rotating bearing ring and the non-rotating bearing ring. The bearing elements are positioned adjacent one another so that the diamond bearing surfaces of the non-rotating bearing ring and rotating bearing ring contact one another.
Bearing elements have traditionally been secured to bearing apparatuses through using various methods, including brazing the bearing elements to a rotating bearing ring and a non-rotating bearing ring of a bearing apparatus. However, conventional brazing techniques typically require exposing the parts to be brazed to high temperatures for extended periods of time to melt a brazing filler metal used to braze the parts. Bearing parts, such as rotating bearing rings and non-rotating bearing rings, are often placed in a heating oven for a few hours in order to heat the parts and the brazing filler metal to the appropriate brazing temperature.